LOS ANGELES (AP) — The Norwegian directing team of Joachim Roenning and Espen Sandberg, whose biopic of World War II resistance fighter Max Manus was a huge hit on home turf, have turned to another native hero for “Kon-Tiki.” One of the most-vaunted escapades of the 20th century, Thor Heyerdahl’s 1947 Peru-to-Polynesia expedition by raft gets glossy big-screen treatment in this efficiently told action-adventure. Delivering visual drama and understated character study, sometimes in disappointingly formulaic fashion, the feature has its incisive moments but falls short as both epic and intimate portrait.

With effective immediacy, the directors dramatize some incidents from Heyerdahl’s 1950 Oscar-winning documentary about the trip, and cinematographer Geir Hartly Andreassen pays tribute in re-created B&W footage of the building of the raft. Too much of the action, though, devolves into close encounters with sharks, scenes that leave the on-deck characters adrift rather than helping to define them.

The film, uniquely shot twice in both Norwegian and English, begins with a brief childhood-episode prologue that makes clear that Heyerdahl is singularly driven. The first words in Petter Skavlan’s screenplay are a warning to the young Thor as he ventures onto the ice: “Don’t do it!” At his peril he ignores the naysayers, and will again 20-odd years later, when, as an accomplished ethnographer, he finds his unconventional theories derided and rejected by every scientific publisher in New York.

The gist of those theories is that 1,500 years earlier, the Polynesian islands were settled not by Asians, the agreed-upon scenario, but by South Americans crossing the Pacific from the east. To prove it, Heyerdahl sets out to make the trip himself, using methods and materials like those available to pre-Columbian Incas, and naming his balsa-wood raft Kon-Tiki, after an Incan sun god.

As he should, the central character remains an enigma, steady and elusive. Portraying the adult Thor, actor Pål Sverre Hagen has something of the young Peter O’Toole about him: tall and lean with blazing blue eyes, evincing charisma and madness nearly in equal measure.

The script supplies expository intros for his five fellow adventurers, but gives most of the actors little chance to differentiate their characters. In some sense it’s enough to know that they’ve embarked on a 4,000-mile journey that most observers consider suicidal: Only one of the six has sailing experience, Thor can’t swim, and their sole concession to modernity is an amateur two-way radio.

In the most substantial supporting role, Anders Baasmo Christiansen plays Herman Watzinger, the divorced engineer who signs on first, eager to shake up his life. He’s a hangdog contrast to Thor’s unflinching willingness to leave behind his wife, Liv (Agnes Kittelsen), and kids. (A long-distance call between husband and wife contains the film’s one glaring anachronism: “You’re breaking up.”) Potent flashbacks show that Thor and Liv once shared a much different life as explorers, a life that he’s not ready to give up.

Herman’s growing doubts about the raft’s construction erode his peace of mind. Amid mounting tensions, the rest of the crew (Tobias Santelmann, Odd-Magnus Williamson, Jakob Oftebro and Gustaf Skarsgård) are more guarded about their faith in the Kon-Tiki. The seventh raft-mate, a parrot named Lorita who received ample screen time in the 1950 film, is presented in a way that telegraphs her fate.

As single-minded as Thor is — Hagen’s pointed stare is loaded with self-certainty and foreboding — he’s also media-savvy, and at the urging of a crewmate turns the mission into a documentary film project. Some of the movie’s most intriguing sequences involve the filmmaking process: the use of a dinghy to get master shots of the raft; the scramble to load the 16mm camera when a spectacular creature surfaces.

This retelling of a bare-bones enterprise by six men took a crew of hundreds, and the results are nothing if not polished, with handsome period detail and visual effects that are convincing, if sometimes ostentatious. The widescreen lensing (the film was shot mainly in and around Malta) doesn’t overdo the sense of wonder and, with a strong assist from the sound design, conveys the men’s vulnerability to the elements.

But too often the directors ride the surface rather than plumb the story’s depths, relying on a score by Johan Söderqvist that abounds in obvious cues. Those signals of danger and grandeur emphasize the otherwise streamlined script’s heavy-handed lapses.